1. Field of the Invention
The present invention relates to a data recording method and data recording apparatus for recording to a tape-form recording medium data that has been sent from a computer, and a recording medium.
2. Description of the Related Art
Data streamers that back up data, such as servers, have been known in the past. With a data streamer, an error correction code is added, and the desired data is recorded at high density.
More specifically, with a data streamer, data to be backed up is partitioned in predetermined block units, and an error correction code is produced by product code method. Further, a data streamer adds error correction codes to the data and records the data in a specific sequence to a tape-form recording medium. Then, the data streamer performs read-after-write, which involves reading the recorded data in order to confirm that the recorded signal was properly recorded to the recording medium. As a result of the read-after-write, retry processing, in which data that could not be read is re-recorded, is executed for any region on the recording medium in which the data that could not be read properly.
Also, with a data streamer, when data is reproduced, a signal read by scanning the tape-form recording medium is processed, so that the recorded data is sequentially reproduced. Here, error correction processing is performed using an error correction code added during recording. Thus, the data streamer backs up and restores the desired data with high reliability (see, for example, Japanese Laid-Open Patent Application 2002-216438 and Japanese Laid-Open Patent Application 2008-262708).
Meanwhile, in recent years we have seen explosive growth in the amount of data being handled, due to the steady increase in the use of computers and the Internet. Accordingly, recording apparatus used for backup need to have larger capacity. A so-called linear tape system has been prominent as one of these high-capacity recording apparatus. With a linear tape system, a plurality of magnetic heads are aligned in the tape width direction, and a signal is recorded by displacing the magnetic heads in the tape lengthwise direction with respect to the slender tape. With a linear tape system, data is recorded to a tape-form recording medium having multiple tracks, in which a plurality of recording tracks are arranged in parallel in the lengthwise direction of the tape-form recording medium.
The above-mentioned recording retry processing is carried out for the purpose of avoiding missed data recording caused by something like defect on the tape-form recording medium, for example. Thus, the data to be re-recorded is re-recorded at another place, rather than at a position nearby in the tape lengthwise direction. When data is re-recorded by retry processing, therefore, it is recorded in a different order from that of the original continuous data. Thus, for data reproduction, a step is required in which re-recorded data is temporarily stored in the memory and then rearranged in the order in which the data is to be reproduced. As a result, the data reproduction response is slower. In particular, since a linear tape system is a method in which a plurality of tracks disposed in parallel in the tape width direction are recorded at the same time, the re-recorded data ends up being re-recorded at a most distant location, and the response is even slower. Also, a larger memory capacity is necessary to temporarily store the data until it is rearranged.
The technology disclosed herein is intended to provide a data recording apparatus, data recording method, and recording medium with which data can be reproduced with better response.